After all that time and work...

Not a big deal. Check to make sure the rear is still square in the chassis (a hit on one side like that can shift it in the U bolts) and unbolt the rear joint, re-seat the joint, and tighten it back up..
OD or lockup adds driveshaft speed which makes any little bit "off" worse. The fact it goes away tells me it's not hugely wrong, but I'd look close at things just to be sure.